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91 Johnson trouble idling

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Dies91

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Hi all I have a 70hp johnson it runs well while in the throttle but runs rough at low speeds and will not idle in neutral at all just dies also has a hard time starting cold and keeping it running to get it warmed up also when I shut it off while fishing and go back to turn it on I have to use the warm up lever otherwise it'll just die immediately. I checked the compression hot #1-115psi, #2-113psi, #3-113psi I did get some gunk in my fuel tank that was clogging the needle valve on the tank and am waiting on a fuel filter to see if that'll help because of possible fuel restriction. I also found this part in the engine hounsing while working on the motor today can't find where its suppose to go though?? 20190811_180924_compress95.jpg
 
No the part isn't cracked or broken Its just a black plastic piece I found a screw too it must of came loose and let the part posted fall off
 
Part unkown
 

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Put up a pic of the side of the motor with the throttle linkages. I have a 92 model might be the same i will look to see if mine has that part.
 
That's the idle stop screw that prevents the idle from dropping below whatever it's been set at. The shorter screw has backed out and let the assembly (pictured) fall off.

There were two different models in 1991... the regular control box combined one... and the tiller model. I looked at both in the book but didn't see anything that looks like that. What's the model number of that engine?

When you find out where it should be attached, install that short retaining screw with a drop of Loc-Tite.
 
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I see by the above graphic that both the idle stop screw and full throttle stop screw are right where they belong, together as a unit as per the parts manual. I have no idea what that other small part is now.
 
Yea I have no clue where it goes and cannot find a place or a threaded hole where it would fit into. When I push the warm up lever all the way down the rpms drop below 800 and the motor just dies
 
Is this engine new to you or have you owned it awhile... and if you've owned it for some time, did it ever run and idle normally? If it ran and idled okay at one time, did this no idle problem just pop up after some maintenance work was done, or was it just a ran okay one day, next day out of the blue this no idle problem was there?

Anyhow... the compression ratios are pretty close but low, however that could be due to a flawed gauge.

Do this... Remove all spark plugs and check the spark which should jump a 7/16" air gap with a strong blue lightning like flame... a real SNAP!... Does it?

You can use a #2 phillip's screwdriver... stick the tip of it inside the curled spring connector that normally clips onto the spark plug, then hold the shank of the screwdriver 7/16" away from the powerhead. Yeah, I know the gap will vary but you get the idea... approximately 1/2" to 5/8", something like that.

Let us know how you do with the spark test.
 
I've had this motor for a few years now and it's always idled and started just fine no issues whatsoever, just ever since getting it going after winter storage its had a hard time.
Okay I'll give that a try and let you know what I find thank you!
 
The part is an adjustment for the timing installee back motor us up and running and idling great again thanks for all the help!
 
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